Straight line shear

ABSTRACT

This relates to improvements in drives for shears, particularly shears for severing gobs from a glass runner. All of the drives incorporate a drive pinion for reciprocating racks which are secured to slides of the shear. The pinion is rotated first in one direction and then in the opposite direction to cause the blades of the shear to first move together and shear a gob, and then move back to the original position. Suitable reversing motors may be utilized, including an electrical servomotor or suitable hydraulic motor. On the other hand, the drive motor may be of the unidirectional type and an oscillating drive member may be incorporated in the drive system for converting the one-directional drive of the motor to an oscillating or reversing output. In addition, the drive of the pinion may be supplemented by a double-acting air motor which is connected to one of the racks. The air motor or cylinder will provide the primary motor power for the shear, but the velocity thereof will be controlled by the servomotor or like motor which is connected to the pinions through a nonreversing drive.

BACKGROUND OF THE INVENTION

This invention relates in general to new and useful improvements instraight line shears for cutting glass runners into individual gobs, andmore particularly to improved rotary drives for such shears.

This invention, in particular, constitutes a modification on the sheardrive disclosed in U.S. Pat. No. 4,215,611 to Francis A. Dahms, grantedAug. 5, 1980, assigned to the assignee of the present invention. Thedisclosure of the aforesaid patent is incorporated herein by reference.

It is known to provide a straight line shear wherein there are twoslides mounted for guided movement towards and away from one another,and arranged in opposed relation. The slides carry cooperating blades.The slides are driven by racks which are interconnected by a pinion. Thedrive unit is in the form of a double-acting air cylinder or linear airmotor which is coupled to one of the racks between that rack and anassociated one of the slides.

SUMMARY OF THE INVENTION

In accordance with this invention, there is provided a rotary drivewhich is coupled to a pinion to effect rotation of the pinion which, inturn, will reciprocate both racks in the required opposite direction. Onthe one hand such a rotary drive unit may be in the form of anelectrical servomotor. Such an electrical servomotor will be controlledby a microprocessor together with a servo controller power switchingdevice. On the other hand, the rotary drive unit may be in the form ofelectric-hydraulic stepping motor or a hydraulic rotary motor with anelectric hydraulic control valve.

The rotary drive unit may be directly coupled to the pinion or may becoupled thereto by way of spur gears or beveled gears. When beveledgears are utilized, the rotary drive unit may be disposed parallel tothe drive mechanism.

In accordance with the present invention, the double-acting air cylindernormally would be discarded. On the other hand, it is feasible toutilize in conjunction with the double-acting air cylinder a rotarydrive unit which would provide the required supplemental torque duringthe shearing operation.

It is also feasible to provide a unidirectional drive unit which wouldbe coupled to a converter having a one direction input and a reversingoutput.

BRIEF DESCRIPTION OF THE FIGURES

In the drawing, wherein throughout like numerals refer to like parts,

FIG. 1 is a schematic plan view showing one embodiment of straight lineshear utilizing an electro servomotor coupled to the drive pinion by abeveled gear;

FIG. 2 is a wiring schematic for the servomotor;

FIG. 3 is a velocity profile for the shear;

FIG. 4 is a schematic plan view similar to FIG. 1 but of an embodimentwherein the rotary drive unit provides a supplemental torque to adouble-acting air cylinder;

FIG. 5 is an enlarged fragmentary vertical sectional view takengenerally along the line 5--5 of FIG. 4 and shows the specifics of therack and pinion type drive;

FIG. 6 is a graph showing the velocity profile of the shear shown in theembodiment of FIG. 4;

FIG. 7 is another schematic plan view of a modified form of shear driveincorporating a one-direction rotation rotary drive unit utilizing adirection converter;

FIG. 8 is a schematic perspective view of the motion converter;

FIG. 9 is a graph showing the velocity profile of the shear shown in theembodiment of FIG. 7;

FIG. 10 is a fragmentary view showing the rotary drive unit of FIG. 1directly coupled to the pinion of the drive assembly;

FIG. 11 is a fragmentary view similar to FIG. 10 and shows the rotarydrive unit connected to the pinion utilizing spur gears;

FIG. 12 is a fragmentary schematic view showing the rotary drive unit asan electric-hydraulic stepping motor; and

FIG. 13 is anaother fragmentary schematic view showing the rotary driveunit as a rotary hydraulic motor with an electric-hydraulic controlvalve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing in detail, reference is first made to FIG.1 wherein there is illustrated a straight line shear generallyindentified by the numeral 20. This shear, in simple terms, includes asupport or frame 22 which has suitable guides for a pair of opposedslides 24, 26 which are mounted within the support 22 for simultaneousreciprocation towards and away from one another. The slides 24, 26 carryblades 28, 30 which cooperate with one another for the purpose ofshearing a glass runner to form gobs. Although two sets of blades 28, 30have been illustrated, it is to be understood that the shear mayincorporate but a single set or may include as many as three sets ormore.

The slide 24 has a bracket 32 to which there is connected an actuatingrod 34. The slide 26 has a similar bracket 36 to which there is coupledan actuating rod 38. The actuating rods 34, 38 are reciprocated by adrive assembly generally identified by the numeral 40. Reference is nowmade to FIG. 5 wherein there is illustrated a typical drive, such as thedrive 40. It will be seen that the support 22 includes a mounting plate42 which carries a housing 44. The housing 44 has mounted therein aguide tube 46 in which there is guidingly mounted one end of the rod 34.The terminal portion of the rod 34 includes a rack 48.

The housing 44 carries a second guide tube 50 in which there is guidedfor reciprocation an end portion 52 of the rod 38. The end portion 52 isalso provided with a rack 54 which opposes a rack 48. A pinion 56 ispositioned between the racks 48, 54 and is meshed therewith. The pinion56 is keyed to a drive shaft 58 which is suitably rotatably journaledwithin the housing 44. For further details of a straight line shear,reference may be made to U.S. patent applications Ser. No. 731,304 byWinzer and Ser. No. 731,303 by Winzer.

In accordance with the embodiment of the invention illustrated in FIG.1, the housing 44 is provided on one side thereof with an adaptor plate60 to which there is secured a right angle drive 62 which includes ashaft 64 which may be a continuation of the shaft 58 or directly coupledthereto. The right angle drive 62 has cooperating mitre or beveled gearswhich are driven through a drive shaft 66 of an electrical servomotor68. It is to be understood that the servomotor 68, when actuated, wouldrotate first in one direction and then reverse its direction of rotationso that the blades 28, 30 will be first advanced together to effect theshearing operation, and then separated to their original positions.

Referring now to FIG. 2, it will be seen that there is illustrated aschematic of the drive for the electrical servomotor 68. Actuation ofthe servomotor 68 is primarily by means of a microprocessor whichprovides the shear motion profile, the microprocessor being identifiedby the numeral 70. The microprocessor 70 has an output 72 connected to aservo controller 74 which effects power switching. The servo controller74 has an output 76 connected to a control head 78 of the servomotor 68for controlling actuation of the servomotor 68.

The control system includes a feedback 80 from the control head 78 tothe microprocessor 70. There is also a tachometer feedback 82 from thecontrol head 78 to the servo controller.

FIG. 3 is a graph plotting velocity against time showing that the shearequipped with the servomotor 68 as illustrated in FIG. 1 will have arapid acceleration to a maximum speed, then a constant speed followed bya rapid deceleration. After the cut or shear occurs, the accelerationand deceleration are reversed.

Although the servomotor 68 has been illustrated in FIG. 1 as beingconnected to the shaft 58 through a right angle drive, it is to beunderstood that the servomotor 68 may be at right angles to the positionof FIG. 1, as is shown in FIG. 10, and directly coupled to the pinionshaft 58.

On the other hand, the servomotor 68 may be coupled to the pinion shaft58 by spur gears 84 as is shown in FIG. 11.

Further, it is to be understood that the servomotor 68 may be replacedby an electro-hydraulic stepping motor system 86, as shown in FIG. 12,which includes a rotary hydraulic motor 88 supplied with hydraulic fluidby a pump 90 which is driven by a stepping electrical motor 92. The pump90 is supplied from a reservoir 94 which receives spent hyraulic fluidfrom the hydraulic motor 88 through a return line 96.

In FIG. 13 there is illustrated another utilization of a hydraulicmotor. In this embodiment a rotary hydraulic motor 98 is directlycoupled to the pinion shaft and the operation thereof is controlled byan electrical or solenoid control valve 100 which controls flow from apump 102 of hydraulic fluid under pressure. The pump 102 receives thehydraulic fluid from a reservoir 104 which receives the return from thehydraulic motor 98.

Reference is once again made to FIG. 5 wherein it will be seen that therod 38 is actually a piston rod of a double-acting linear air motor orcylinder generally identified by the reference numeral 106. The airmotor 106 includes a cylinder 108 in which a piston 110 is mounted, andwhich piston 110 has a piston rod 112 which is coupled to or may formthe rod 38.

The piston rod 112 also extends out through the opposite end of thecylinder and is connected to the rod portion 52.

From the description of FIG. 5, it will be seen that the shear may beactuated utilizing the double-acting air motor 106. However, it has beenfound that beneficial results may be obtained with the shear arrangementshown in FIG. 4 and generally identified by the numeral 116. The shear116 is indentical to the shear 20 with the exception of theincorporation of the double-acting air cylinder 106. In this embodimentof the shears, the servomotor 68, or similar motor, may be utilized tosupplement the drive provided by the air cylinder 106.

It is to be understood that the servomotor 68 will be driven in themanner described with respect to the shear 20. In this embodiment of theinvention, sufficient air pressure is supplied to the air cylinder 106to move the shear in excess of the desired cutting velocity. Themicroprocessor 70 provides a signal to the electric air control valve toapply air to the cylinder to move the shear for the cutting of a gob.However, if the right angle drive is a locking worm and wheel gearreducer 118, the air motor cannot actuate the shear until the servomotor68 permits such movement. Thus, the servomotor 68 controls the motion ofthe cutting stroke and the air motor provides the power.

Further, and most particularly, the torque applied to the pinion by theservomotor supplements the force applied to the shear by the aircylinder.

It is to be understood that both the air to the air cylinder and thedirection of rotation of the servomotor is reversed for the returnstroke of the shear.

A typical velocity profile for the shear arrangement of FIG. 4 is shownin the graph of FIG. 6.

Reference now is made to the embodiment of FIG. 7 wherein there isillustrated a shear generally identified by the numeral 110. The shear110 will be identical to the shear 20 with the exception of the rotarydrive unit. In lieu of the servomotor 68 being coupled to the pinionshaft 58 by way of a conventional right angle drive, there is anoscillating drive 112 between the servomotor 68 and the drive unit 40.The drive 112 may be a purchased item and is best illustrated in FIG. 8.The illustrated drive unit 112 may be what is conventionally known as aFerguson drive, or the equal. The drive 112 will be provided with aone-direction rotational input shaft 114 and an oscillating or reversingrotation output shaft 117. Thus, the servomotor 68 or other type ofdrive motor need not be of the reversing type.

FIG. 9 is a graph showing the plotting of velocity against time for theshear 110 illustrated in FIG. 7.

It is to be understood that the electric servomotor 68 may be replacedwith other types of drive motors as previously discussed.

It is also to be understood that the specific drives for the variousshear arrangements discussed hereinabove provides for high-speedoperation with maximum control so that the shearing of gobs may beincreased while at the same time the resistance to the movement of theglass runner by the blades of the shear may be decreased.

Although only several preferred embodiments of drives for a straightline shear have been illustrated and described herein, it is to beunderstood that minor variations may be made therein without departingfrom the spirit and scope of the invention as defined by the appendedclaims.

It is claimed:
 1. In a straight line shear for forming glass gobs saidshear comprising a pair of opposed slides carrying opposed blades, guidemeans guiding said slides for movement along a predetermined path, apair of opposed spaced apart toothed racks coupled to said slides, and apinion meshed with both of said racks whereby when said pinion isrotated said racks move in opposite directions, the improvementcomprising:a double-acting linear fluid motor couipled to one of saidracks to drive said rack and alternately drive said blades in shearingand opening motions, a servo, rotary drive motor coupled to said pinionto rotate said pinion whereby said servo motor drives said racks andsaid blades, and means coupled to said servo motor for controlling saidservo motor and thereby regulating the motion of said blades and furthercomprising: means defining a source of pressurized fluid for said linearfluid motor, the fluid pressure being large enough to move said bladesnear to or greater than a desired cutting velocity and wherein thecontrol means and said servo motor adjust the velocity of said linearfluid motor to said desired cutting velocity.
 2. An improvement to astraight line shear as set forth in claim 1, wherein said linear fluidmotor comprises a piston and cylinder assembly.
 3. An improvement to astraight line shear as set forth in claim 1, further comprising:alocking worm gear and worm wheel connected between said servo motor andsaid pinion gear to facilitate said servo motor in limiting the motionof said linear fluid motor.
 4. An improvement to a straight line shearas set forth in claim 1, wherein the control means comprises means forsensing the angular position of said servo motor to determine thepositions of said blades.
 5. An improvement to a straight line shear asset forth in claim 1, wherein the control means further comprises meansfor sensing the angular velocity of said servo motor to determine thespeed of said blades.
 6. An improvement to a straight line shear as setforth in claim 5, wherein said control means further comprises means forcontrolling said servo motor to cause said blades to move in atrapezoidal velocity pattern.
 7. An improvement to a straight line shearas set forth in claim 6, wherein said control means includes means forsensing the angular position of said servo motor to determine theposition of said blades.
 8. An improvement to a straight line shear asset forth in claim 1, wherein the control means is programmed to utilizesaid servo motor to prevent said linear fluid motor from driving saidblades past an optimal end shearing position.
 9. An improvement to astraight line shear as set forth in claim 1, wherein said servo motorcomprises an electro-hydraulic stepping motor.
 10. An improvement to astraight line shear as set forth in claim 1, wherein said servo motorcomprises a hydraulic rotary motor having an electric hydraulic controlvalve.
 11. An improvement to a straight line shear as set forth in claim1, wherein said servo motor includes a unidirectional power unit and aone direction transfer device having a reversing output.
 12. Animprovement to a straight line shear as set forth in claim 1, whereinsaid servo motor is electric.